Rudder Trailing Edge

[Low & Slow]

Hello All,

I'm getting ready to rivet the rudder, and was wondering what the consensus was on the need to put a slight bend in the trailing edge of the skins to prevent separation during the riveting process? And if needed, what is the best way to bend it? I have an edge rolling tool, but the trouble Mike Schipper had with his trailing edge using a roller has me spooked. Van's instructions also warn about this problem. Any advice would be appreciated.

[scard]

I didn't find any need to roll the trailing edges. Just don't over drive the rivets too much and it will be fine. I used proseal on all of my -9 trailing edges. I'm very happy with mine.

[airguy]

Same here - proseal, with no roll, they came out great. I also alternated the shop head direction every other rivet for all my trailing edges to prevent riveting in any type of curve or bow.

I did have one or two spots on my aileron trailing edges where I thought the skins were diverging ever so slightly while clecoed, and while I was riveting that trailing edge I "rolled" the flat set off the trailing edge at the end of the string of impacts, giving 3 or 4 hits at an angle, pushing the skin down hard onto the trailing edge (with a back rivet plate under it), this gave me very good results with a nice tight trailing edge. Be careful not to get carried away here, you can end up thinning the skin and spreading it out past the normal end of the trailing edge, and have to file it down to remove that stretched material.

[N55CU]

You will find that the trailing edge will start bending as you start rivetting. That's why you alternate the shop head's and don't set them too hard to begin with. I ending up setting mine with my gun. Laid the rudder on top of the backrivet plate and used the flush rivet attachment with the rubber guard. You can't use the squeezer as it will dimple the skin because of the slight angle where the edges meet.
Randy "Utz"
N55CU / RV-7 / 180 hrs
Charlotte, N.C.

[waynestir1]

I prosealed mine with an Aluminum angle cleco'd behind it to keep it straight. When I went to rivet, The proseal kept it all nice and in place.

I rivetted by backrivetting one side, about every 5th one, setting them about 1/2 way, then set the rest 1/2 way. Flipped it over and used a flush set on the back rivet plate, and finished it. The rivets look really good, and the trailing edge is nice and straight.

This is definitly the way to go.

[Vlad]

I saw a homebuild at Oshkosh 07 with trailing edges very thin almost closed. I asked the owner how he did that. He said the skins were lightly bent before riveting but he suggested not to do so without any prior experience. He didn't use any gluing substance.

[Greg Arehart]

I agree with Scott, just don't overdrive the rivets and you should be fine. I did not alternate shop heads (though that seems in retrospect like a good idea) - all are on the same side and mine came out perfectly straight. I did not use proseal or any glue to hold them together. I have seen where folks have ground down squeezer sets to get the proper angle, but I had no problem with a gun and backrivet plate. Start to set the rivets straight on (just like "normal" rivets) and then tilt the gun as you finish the rivet so that the gun is at 90 degrees to the rudder skin. Again, I think the key is not overdriving these, or you will put an arc in the trailing edge.

greg

[Low & Slow]

Thanks to all who responded. I'm happy with the consensus view because my skins come together nicely right now when clecoed and I wasn't looking forward to possibly messing them up.

[Don Jones]

I used my hand squeezer to partially set the rivets before turning it over on the back rivet plate and finishing them off. I did not roll the edges on them either. They came out terrific. You do have to be careful not to get carried away with the squeezer, but I couldn't bring my self to get the back rivet set near those rivets. I had visions of huge smileys I used this method on the ailerons without proseal on them and both are straight and not a ding in sight!

[aerhed]

After seeing about a million wavy Cessna surfaces and stop-drilling 2 million cracks and replacing a hunnerd flap/elevator/aileron skins trying to match V-ribs semi-unsuccessfully (slight exaggerashuns) I'm really favoring a good bonding like the pro-seal deal. These trailing rivet joints aren't very good on their own, any time rivets are unsquare weird things happen below the head. Bends, bulges, etc. put forces on the skin you can't control. The nasty goo helps surround the shank and fill the little triangular cavity helping keep the rivet driving forces straight down the shank. I've wondered if I could grind a pair of flush sets to the T.E. angle and get a straight squeeze. I can picture a gator squeezer with angled sets doing a nice squeeze.